Name a common signaling molecule involved in the regulation of bronchial constriction.

Histamine is a common signaling molecule that plays a significant role in the regulation of bronchial constriction. It is primarily released from mast cells during an allergic response or in response to certain stimuli. When histamine is released, it binds to specific receptors on smooth muscle cells in the bronchial airways, leading to bronchoconstriction, which narrows the airways and can result in difficulty breathing.

This mechanism is particularly relevant in conditions such as asthma and allergic reactions, where histamine levels can rise significantly, contributing to the symptoms experienced by affected individuals. Understanding the role of histamine is vital for developing treatments aimed at mitigating bronchoconstriction, such as antihistamines, which can block its action and help alleviate symptoms.

While other molecules like nitric oxide, adrenaline, and cortisol have roles in respiratory function and inflammatory responses, histamine is the most directly involved in bronchial constriction due to its action on bronchial smooth muscle.